Clear-aligner treatment uses a plurality of customized aligners to adjust a patient's teeth. Each aligner applies pressure to a patient's tooth or teeth which causes the tooth or teeth to move into a particular position within the aligner. If a patient's teeth require rotation or extrusion, then aligners alone may be insufficient to achieve such movement. In order to achieve rotation or extrusion of a particular tooth an elastic band may be used to apply a force to the particular tooth. This is typically accomplished by bonding a button to the particular tooth to establish a first anchor point and then disposing an elastic band over the button and a second anchor point. The elastic band applies a force to the button and the particular tooth causing the tooth to gradually move towards the second anchor point. A practitioner selects a second anchor point to apply a specific force vector to a button and a particular tooth wherein the specific force vector has a direction configured to move the particular tooth into a particular position within an aligner. A practitioner is generally limited in selection of a second anchor point by considerations of patient comfort and availability of potential anchor sites.